On Friday, the South Yorkshire police authority debated extending the policing role of community support officers in order to free up police officers. In an era of less money and more crime, something has to give. The question is whether the number of police officers out on the beat is the right cut to make. The chief constable, David Crompton, thought it was a simple question of value for money and the row was nothing but a storm in a teacup. He may be right. One of the strengths of British policing is that individual forces can develop individual strategies. But it is a decision that goes to the absolute core of police philosophy.

The effects of public austerity were not the only reason why South Yorkshire police were in the headlines on Friday. Twenty-three years ago this weekend, 96 Liverpool supporters died in the Hillsborough disaster. The police blamed the fans' behaviour. On the contrary, said the official inquiry by Lord Justice Taylor, it was mismanagement by the police themselves. Five years earlier, the force was involved in the "Battle of Orgreave". It was another public order disaster, an operation involving a mounted charge and a total of 4,000 officers, many in full riot gear, which led to the arrest of 95 miners. Branded the enemy within by the then prime minister, Margaret Thatcher, the miners were accused of attacking the police. But the case against them crumbled when the police evidence was found to be cooked up.

Yesterday, a Merseyside MP, Maria Eagle, and the defence lawyer Michael Mansfield QC argued that the two events were linked by a culture of impunity that had been allowed to develop. There is plenty of evidence to support their claim. But this is a story that raises questions which go far beyond the way one police force was managed more than 20 years ago. The common thread connecting past and present runs through the inner-city riots triggered by police racism that reappeared last year in a form familiar since the early 1980s. Nor is it just a story about a failure in policing. For the idea that striking miners, and later Liverpool football fans, were groups apart where normal policing rules need not apply was encouraged by politicians, and even, notoriously, by sections of the media. There was a culture of impunity because there was a culture of exceptionalism: some groups weren't entitled to be policed according to the normal rules.

As inquiries into last August's riots have suggested, London, Britain's most diverse city in terms of wealth as well as race, suffers from this exceptionalism in its most acute form. Many black residents of inner-city boroughs feel victims of over-surveillance and under-protection. Politicians' remarks about a "feral underclass" carry more than an echo of earlier scenes of disorder. As we have reported, some officers behaved wrongly at the time of the riots and in their aftermath. But – as Liberty pointed out to MPs inquiring into the riots – their senior officers robustly resisted all calls for military intervention, water cannon and plastic baton rounds. There is also, at last, a sense of urgency about racism.

At the heart of the way Britain is policed is that it is a matter not of force but of consent, and police officers – while possessing unique powers of arrest – are citizens too. Sustaining this principle, one which has motivated modern policing since Sir Robert Peel first articulated it, should be a priority for all reformers. And that is where consideration of the proper limits of the use of community support officers matters. If police officers are no longer in routine contact with law-abiding citizens, it must become that much less likely that they will anticipate community concerns – and, just as important, that communities will feel the police are on their side. That matters for the intelligence-gathering that underpins wider security. And it is vital for the neighbourhood policing that voters want.